1. Field of the Invention
This invention relates to a cogeneration system, particularly to a cogeneration system that self-diagnoses battery voltage and the like.
2. Description of the Related Art
In recent years, cogeneration systems have been developed that are equipped with an internal combustion engine-driven generator for installation in an AC power supply line between a commercial power network and an electrical load for supplying power to the electrical load in interconnection with the power network and also for supplying hot water or the like heated using exhaust heat from the engine to a thermal load. Among such the systems, there is known a type of a cogeneration system capable of self-diagnosing an abnormality, as taught, for example, by Japanese Laid-Open Patent Application No. Hei 1-237344.
In a technique disclosed in the prior art, an expert system using inference is introduced for self-diagnosing an abnormality of a cogeneration system.
A cogeneration system is continuously or intermittently operated in interconnection with the commercial power network at the time the power network works normally, while it is operated solely or independently when a failure such as a power outage occurs in the power network. Although the cogeneration system can start operating by being supplied with power from the power network when it is normal, the system has to start with power from a built-in battery when a failure such as a power outage occurs in the power network. In this case, if the battery has degraded, the system can not be started. The same can be applied when a failure happens in the engine.